Setting up the Assembly project

Unfortunately, Visual Studio, by default, has no template for Assembly language projects, therefore, we have to create one ourselves:

1. Launch Visual Studio and create an empty solution, as shown in the following screenshot:

Look at the bottom-right part of the Start Page window, where you will see the option to create a blank solution. If there is no such option, click on More project templates... and select Blank Solution from there.

1. Once the solution has been created for us, we may add a new project. Right-click on the name of the solution and go to Add | New Project:

As Visual Studio has no built-in template for an Assembly project, we will add an empty C++ project to our solution:

1. Choose a name for the project and click on OK. There are a two more things we have to do before we can add source files. To be more precise, we can add sources and then take care of these two things, as the order does not really matter. Just keep in mind that we will not be able to build (or, correctly build) our project before we take care of these.

1. The first thing to take care of is setting the subsystem for the project; otherwise, the linker will not know what kind of executable to generate.

Right-click on the project name in the Solution Explorer tab and go to Properties. In the project properties window, we go to Configuration Properties | Linker | System and select Windows (/SUBSYSTEM:WINDOWS) under SubSystem:

1. The next step is to tell Visual Studio that this is an Assembly language project:

1. Right-click on the project name and go to Build Dependencies in the context menu, click on Build Customizations…, and from the build customizations window, select masm(.targets, .props):

1. We are now ready to add the first Assembly source file:

Unfortunately, Visual Studio does not seem to be prepared for Assembly projects and, therefore, has no built-in template for Assembly files. So, we right-click on Source Files in the Solution Explorer, select New Item under Add, and since there is no template for the Assembly source file, we select C++ File (.cpp), but set the name of the file with the .asm extension. We click on Add, and voila! Our first Assembly source file is shown in the IDE.

1. Just for fun, let's add some code:

        .686
        .model flat, stdcall

        ; this is a comment
        ; Imported functions
        ExitProcess proto uExitCode:DWORD
        MessageBoxA proto hWnd:DWORD, lpText:DWORD, lpCaption:DWORD, 
        uType:DWORD

        ; Here we tell assembler what to put into data section
        .data
            msg db 'Hello from Assembly!', 0
            ti db 'Hello message', 0

        ; and here what to put into code section
        .code

        ; This is our entry point
        main PROC
            push 0              ; Prepare the value to return to the 
                                ; operating system
            push offset msg     ; Pass pointer to MessageBox's text to 
                                ; the show_message() function
            push offset ti      ; Pass pointer to MessageBox's title to 
                                ; the show_message() function
            call show_message   ; Call it

            call ExitProcess    ; and return to the operating system
        main ENDP

        ; This function's prototype would be:
        ; void show_message(char* title, char* message);
        show_message PROC
            push ebp
            mov  ebp, esp
            push eax

            push 0              ; uType
            mov  eax, [dword ptr ebp + 8]
            push eax            ; lpCaption
            mov  eax, [dword ptr ebp + 12]
            push eax            ; lpText
            push 0              ; hWnd
            call MessageBoxA    ; call MessageBox()

            pop  eax
            mov  esp, ebp
            pop  ebp
            ret  4 * 2          ; Return and clean the stack
        show_message ENDP
        END main

Do not worry if the code does not "speak" to you yet; we will begin to get acquainted with the instructions and program structure in Chapter 3, Intel Instruction Set Architecture (ISA).

Right now, let's build the project and run it. The code does not do much, as it simply displays a message box and terminates the program:

By now, we have a working setup for Assembly development on Windows.